Marcasite
| ID | 249 | |
|---|---|---|
| Mineral | Marcasite | |
| Location | Ilsfeld - Baden-Württemberg - Germany | |
| Fluorescence | LW-UV: close SW-UV: close |
|
| Mindat.org |
View Marcasite information at mindat.org |
|
Mindat data
| ID | 2571 |
|---|---|
| Long ID | 1:1:2571:9 |
| Formula |
FeS2
|
| IMA Status |
0 1 |
| Other Occurrences | Most frequently found in sedimentary rocks and coal beds, as a replacement mineral forming fossils, it is a mineral of low-temperature, near-surface, environments, forming from acid solutions. Pyrite, the more stable form of FeS^2, forms under conditions of higher temperatures and lower acidity or alkaline environments. |
| Discovery Year | 1845 |
| Diapheny | Opaque |
| Cleavage | Distinct on {101}. {110} in traces. |
| Tenacity | brittle |
| Colour | Pale brass-yellow, tin-white on fresh exposures. |
| Hardness (min) | 6.0 |
| Hardness (max) | 6.5 |
| Lustre | Metallic |
| About the name | Early use of the word marcasite seems to have been unspecific. The word is Arabic or Moorish and was applied to pyrite and similar metallic bronze colored minerals. Walter Pope (1665) mentioned marcasite occurring in the mercury ores of the Idria Mine, Cividale del Friuli in the Julian Alps of Slovenia: "There are also several Marcasites and stones, which seem to have specks of Gold in them, but upon trial they say, they find none in them. These round stones are some of them very ponderous, and well impregnated with Mercury; others light, having little or none in them." The mercury ore at Idria does contain metallic golden specks of what is now called marcasite, but it also has metallic golden pyrite. Johnathan Hill used the name marcasite in 1771, but his usage was also indiscriminate and was a term for any massive "pyrites" or "mundic". In 1845, Wilhelm Karl von Haidinger defined marcasite as the mineral is known today. |
| Streak | Dark-gray to black. |
| Crystal System | Orthorhombic |
| Cleavage Type | Distinct/Good |
| Fracture type | Conchoidal,Sub-Conchoidal |
| Morphology | Crystals usually tabular on {010}, also pyramidal, faces often curved, frequently twinned; also stalactic, globular, or reniform with radiating internal structure. |
| Twinning | Common on {101}, forming "swallowtail" contact twins; this may be repeated to form stellate fivelings. Less common on {011}. |
| UV | Not fluorescent in ultraviolet light |
| Comment Luster | Frequently iridescence obscures the luster and color |
| shortcode_ima | Mrc |
| Group | Marcasite Group |
Details
Price: € 15
Dimensions: Not registered
Weight: 208 g
Visibile in overview:
Notes:
| Symbol | Element | |
|---|---|---|
| Fe | Iron | |
| S | Sulfur |